Fears Oracle Team USA may lodge a late protest against Team New Zealand have intensified, with America's Cup race management paying a couple of visits to the Kiwi base in Bermuda today.

A group of four members of the measurement committee - the group tasked with ensuring each of the race boats comply with the design rules - spent an hour at the Team NZ base this morning, before returning later in the afternoon after the boat had come off the water.

Rumours have been circulating Oracle had issued a claim on non-compliance against Emirates Team New Zealand after the Kiwi team's rollicking 4-0 start to the Cup match.

Chief measurer Ken McAlpine today confirmed to the Herald neither team had lodged an official protest, but said race management were "very busy" dealing with last minute issues.

Prior to visiting Team NZ this morning, McAlpine said the measurers had spent an hour and a half at the Oracle base following up on concerns raised. McAlpine would not go into details of what the measurement committee had been asked to assess, but said it is their duty to properly satisfy any questions that are asked by the competitors.

"When we come into Team New Zealand we are representatives of Oracle, and when we go across to Oracle we are representatives of Team New Zealand, and that's the way we have to look at it," he said.

Under the rules that govern the America's Cup match, each team has just one formal protest or "claim of non-compliance" up their sleeve. There were concerns coming into the event that placing a limitation on the number of protests left the rules open for exploitation once a team had burnt their one protest. But America's Cup chief umpire Richard Slater said earlier this month teams have other ways of bringing potential compliance issues to the attention of the measurers.

"There is a tradition in the America's Cup where most teams will start this process not by protesting non-compliance, but by expressing their 'disappointment, desire, concerns' to the measurement committee, and in my experience the measurement committee will the go and check every boat for that concern," said Slater.

That appears to be the process both teams are going through now.

With fixed on-board cameras providing a close-up view of what is happening on each of the race boats, teams have a greater understanding of what equipment and software their rivals are using than ever before.

If they see something they believe may be pushing the boundaries of the design rules, they can raise it with the measurement committee.

Regatta director Iain Murray said the measurers are already familiar with every detail of the boats.

Explaining the measurement process earlier this month, Murray said the teams are under constant surveillance of the measurement committee. Each syndicate must get their boat certified every day before taking to the race course, while there is a measurer on the team's chase boat during racing to monitor compliance.

"The measurers get there at 7.30 each morning and they chaperone the boats out of the sheds and check off [all the hardware] that is assembled on the boat. They are with the team when it comes out of the shed, through its launching, through racing, and to the time they return to the shed. Big Brother is watching the whole time and of course we are trying to front foot it so there are no issues."

-NZ Herald